1. Field of the Invention
The present invention is in relation to an integrated circuit comprising metal-oxide-semiconductor (MOS) transistors and/or bipolar transistors and load resistors which are arranged as thin-film elements on the field oxide zones which separate active transistor zones, with gate electrodes and/or emitter or base terminals comprising a double layer of polycrystalline silicon and a silicide of a refractory metal, and further in relation to the process for the production thereof.
2. Description of the Prior Art
Modern processes for the production of bipolar transistors and MOS transistors having high switching speeds employ polycrystalline silicon layers as diffusion sources, terminal and gate materials. A further great advantage is the fact that resistors required in the circuits can be arranged as thin-film elements, in an extremely space-saving at low-capacitive design, on the field oxide zones which separate the active transistor zones of the circuit. A transistor circuit of this type is described, for example, by N. C. C. Lu et al and the publication IEEE Trans. EI. Dev., ED-29, pages 682 to 690, April 1982.
In a mixed bipolar complementary-metal-oxide-semiconductor (CMOS) transistor circuit, the gate electrode, composed of polycrystalline silicon, can be used to form load resistors. Because of the higher work function of the gates, silicides of refractory metals or double layers of polycrystalline silicon and metal silicides are used as gate material. However, because the low sheet resistance (2-5 Ohm per square), these are not suitable to form load resistors with a sheet resistance in the kilo-ohm range and higher.